1. Field of the Invention
The present invention is concerned with techniques for providing non-destructive testing of an insulated electrical region, and is more particularly concerned with impressing a voltage into an electric component of an integrated circuit, which has a passivating layer of electrically insulating material, through the utilization of an electron beam.
2. Description of the Prior Art
It is well known in the art that an electron beam can be used for proximity testing of the function of electronic components, particularly of integrated circuits. For this purpose, the integrated circuit is mounted into the sample chamber of a scanning electron microscope. The primary electron beam triggers secondary electrons on the surface of the component, the energy of which can be measured with a spectrometer.
In order to check such electronic components, voltages can be impressed from the exterior. For this purpose, mechanical probes are placed on conducting areas of the component. It is, however, customary in case of such components having a base of semiconductor material, to provide the surface, for the sake of passivation, with a layer of electrically insulating material, for example, silicon oxide (SiO) or silicon dioxide (SiO.sub.2). The passivating layer covers the electrically conducting areas of the component and prevents contacting by a mechanical probe without destruction of the surface layer.
With the primary electron beam of a scanning electron microscope, it is possible to inject charges into the surface of the insulating passivating layer. This injection charge carriers into the isolator can be used for analysis of leakage currents, as suggested in "Scanning Electron Microscopy", Part IV-IITRI, Chicago/USA, SEM, April 1976, pp. 515-520. A tampering into the electrical behavior of the circuit is thus, however, not possible.